The authoritative public forum
  for Metal Finishing since 1989
-----

9th Grade Science Project on Electroplating

Dear Forum members. I am doing a science experiment as an entry to Science Leadership Academy. I have chosen electroplating as the topic, but need a control and a variable for the project. Please help.

Jon M. [surname deleted for privacy by Editor]
student - Philadelphia
November 21, 2010

---

Hi, Jon.

Please explain in your own words what you mean by control in this context and what you mean by variable. Then I can answer.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 22, 2010

---

The most common variables would be temperature, concentration of the metal ion and pH.
Hold all but one constant.

James Watts
- Navarre, Florida
November 22, 2010

---

Hi, thank you for responding! I was wondering if there are different types of solvents that can be used in this project(NICKEL CHLORIDE/ SODIUM CHLORIDE / ETC.)
My control is going to be the type of metal I will be transferring. I am transferring copper onto brass and don't have the facilities for acids.

Jon M. [surname deleted for privacy by Editor]
- Philadelphia, Pennsylvania, USA
November 23, 2010

---

November 23, 2010

Hello again, Jon.

Vinegar is a mild and common household acid that you should consider using for your project. Metals tend to precipitate out as hydroxides if the electrolyte is neutral or slightly basic, and you obviously can't electroplate a metal out of the solution if it's not in the solution. The solubility of copper is only a few parts per million at pH7 and is zero at not much over pH8. Please see the solubility table of metals at various pHs.

I don't think you should use nickel chloride in an electrolyte for copper plating because it will tend to drive copper out of solution, and the nickel will tend to plate out.

Please review with your teacher the meaning of "control". I don't see how "the type of metal I will be transferring" can be a control unless you are implying that you will be measuring how much metal you transfer and you will be comparing it to the amount of metal that Faraday's Law predicts.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

---

Copper is a product, not a variable. As in A + B = C. Now if you specify hardness or malleability or conductivity or purity or some other measure, then that would become C1 or C2 or--ETC. It is still an outcome, not a variable or a control.

When you limit your process to no acids, You eliminate anything that you can afford as I am sure that you can not use cyanide.

As Ted said, vinegar ⇦in bulk on eBay or Amazon [affil links] is acetic acid which is a mild acid. Do NOT use the word weak acid as that means something totally different and includes hydrofluoric acid which is one of the nastiest common acids available.

Simplify your experiment to try different concentrations of the vinegar or the concentration of the metal ions or the temperatures used. What will be a measure of your product? Weight, color or?

James Watts
- Navarre, Florida
November 26, 2010